Strawberry plant named PS-776

ABSTRACT

This invention relates to a new and distinct winter planted short-day-type variety of strawberry known as `PS-776`. This new variety is primarily adapted to the growing conditions of the central coast of California. The new variety is particularly characterized by its small round leaves with many shallow serrations, long inflorescences which are easily visible above the canopy of the plant much of the season, very uniformly smooth shaped berries and its ability to remain in fruit production from mid to late April through November. The fruit is very attractive with acceptable flavor and juiciness as well as excellent firmness and holding quality.

SUMMARY OF THE INVENTION

The present invention relates to a new and distinct short-day-typestrawberry variety designated as `PS-776`. This new variety is a resultof a cross of the variety claimed in U.S. Pat. No. P.P. 8,205, nowdesignated `PS-118`, and the variety claimed in U.S. Pat. No. P.P.8,346, now designated `PS-308`. The variety is botanically known asFragaria×ananassa Duch.

This new variety of strawberry resulted from a breeding program jointlysponsored by Plant Sciences, Inc. and Berry R & D, Inc., both ofWatsonville, Calif., with the objective of developing new and distinctstrawberry varieties. The seedling resulting from the aforementionedcross was asexually propagated by stolons in a nursery located in LassenCounty, Calif., and was subsequently selected from a controlled breedingplot in Watsonville, Calif. in 1991. After its selection, the newvariety was further asexually propagated in Lassen County, Calif. bystolons and extensively tested over the next several years in fruitingfields near Watsonville, Calif. This propagation and reproduction hasdemonstrated that the combination of traits disclosed herein ascharacterizing the new variety are fixed and remain true-to-type throughsuccessive generations of asexual reproduction.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying color photographs show typical specimens of the newvariety at various stages of development as nearly true as it ispossible to make in color reproductions:

FIG. 1 shows typical plant parts of the new variety including leaves(both the lower surface of a mature terminal leaflet, and the uppersurface of a mature trifoliate leaf). Cross-sectional and longitudinalviews of mature fruit illustrate typicallight flesh and conspicuous coreand core cavity. Also shown is an inflorescence with the primary berrybeing mature and harvestable demonstrating typical fruit distribution,shape and size;

FIG. 2 shows typical plant growth, flowering and fruitingcharacteristics in late July 1995. The photograph illustrates the plantvigor, long inflorescences, and upright growth habit;

FIG. 3 shows a close-up of typical plant growth, flowering and fruitingcharacteristics in late July 1995;

FIG. 4 shows a close-up view of fruit harvested in mid July 1995 andpacked in a standard twelve-dry-pint-crate;

FIG. 5 discloses the isozyme banding patterns for `PS-776`, comparedwith those of `PS-118` and `Selva`.

DESCRIPTION OF THE NEW VARIETY

`PS-776` is primarily adapted to the climate and growing conditions ofthe central coast of California. This region provides the necessarywinter temperatures required for it to produce a strong vigorous plantand to remain in fruit production from April through November. Thenearby Pacific ocean provides the needed humidity and cool temperaturesto maintain fruit quality during the summer production months.

`PS-776` is a moderately vigorous plant. When provided with optimumchilling in the nursery propagation fields prior to being dug, andartificial cold storage prior to being planted, the plant of the newvariety tends to be smaller and less vigorous than both `PS-118` and`Selva` (U.S. Pat. No. P.P. 5,266). `PS-776` generally produces fewerrunners per plant in the fruiting fields than both `PS-118` and `Selva`.The foliage of the new variety is slightly darker in color than `Selva`and slightly lighter than `PS-118`. `PS-776` leaves are smaller thanboth `PS-118` and `Selva` and more rounded in shape than `Selva`.`PS-776` has more serraions per leaf and shallower serrations than both`PS-118` and `Selva`. `PS-776` petioles are similar in length, butsmaller in diameter, than both `PS-118` and `Selva`. Table 5 summarizesfoliage characteristics of `PS-776`, `PS-118` and `Selva`.

`PS-776` is capable of long season fruit production with fruit ofacceptable size and excellent quality during the entire season whenprovided with optimum chilling in the nursery propagation fields andartificial cold storage prior to being planted. Initial studies indicatethat `PS-776` has a lower vernalization (chilling) requirement than`Selva` for optimum fruit production and plant vigor. Fruit productionbegins as early as mid April in Salinas, Calif., and may continue intoNovember if rains and cold temperatures do not prevent the harvest.April production is later and lighter than `Selva` and similar to`PS-118`. `PS-776` season average fruit size is smaller than both`PS-118` and `Selva` with total yields comparable to both (Table 1).

The fruit of `PS-776` is smoother with fewer longitudinal creases andbetter overall appearance, gloss and skin firmness than `Selva`. Table 3summarizes fruit quality performance ratings. The primary berries of`PS-776` tend to produce seedy tips at the apex of the fruit primarilyduring the early spring and under adverse weather conditions. Incomparison, `PS-118` tends to produce seedy tipped fruit during much ofthe season. The seeds of `PS-776` typically do not protrude, or onlyslightly protrude, from the surface of the fruit. In contrast `PS-118`tends to have seeds that protrude more consistently from the fruitsurface. The fruit color of `PS-776` is noticeably darker than `Selva`but similar to `PS-118`. `PS-776` fruit has a lighter internal fleshcolor than either `PS-118` or `Selva`. The fruit of `PS-776` is verysmooth and symmetrically conic. It is more conical in shape (lessrounded) than the fruit produced by `PS-118`. The fruit is also smootherand more uniformly conic, with fewer longitudinal creases and irregularshapes, than `Selva`.

Flavor panels have rated `PS-776` as having better flavor than `Selva`(Table 4). The fruit of `PS-776` is more susceptible to skin crackingfrom rain than the fruit produced by either `PS-118` or `Selva`. Thetotal inflorescence length of `PS-776` is considerably longer than`PS-118`, especially during the summer months. The average primarypeduncle is longer and thinner than both `PS-118` and `Selva`. Theprimary pedicel is also shorter and thinner than both. Flowers andripening fruit are noticeably more visible above the canopy of the plantduring much of the season as compared to `PS-118` and `Selva`. Table 6summarizes inflorescence characteristics of `PS-776`, `PS-118` and`Selva`.

SPECIFIC DESCRIPTION OF THE NEW VARIETY

The following is a detailed description of `PS-776`, including thevariety's morphological, electrophoretic, pest and disease reactioncharacteristics. This detailed description is based on observationstaken during May through July of 1995 in Salinas, Calif. In thoseinstances where a characteristics was rated at different times the dateof the evaluation is listed. These measurements and ratings were madefrom plants dug from a high-elevation nursery located in Lassen County,Calif. in October 1994 and planted in Salinas, Calif. in November 1994.The phenotypic characteristics of the new variety may vary slightly,depending upon variations in environmental factors, including weather(temperature, humidity and light intensity), day length, soil type,location, and time of year, without a change in the genotpe of theplant. `PS-776` has not been observed under all possible environmentalconditions. Color terminology follows the Munsell Book of Colors,Munsell Color, Baltimore, Md. (1976).

FRUIT CHARACTERISTICS

`PS-776` fruit, fruit production and runner production (fruiting field)characteristics are compared to those of `PS-118` and `Selva` in Table1.

                  TABLE 1                                                         ______________________________________                                        1994 market fruit yield, fruit size and runner production                     characteristics from plants harvested from April through                      November 1994 of `PS-776` from a high elevation nursery                       (McArthur, California) compared with standard cultivars dug                   October 20, 1993 and planted November 9, 1993 in Salinas,                     California.                                                                            APRIL    TOTAL    AVERAGE  AVERAGE                                            YIELD    YIELD    FRUIT    RUNNERS/                                  CULTIVAR GM/PL    GM/PL    SIZE G/FR                                                                              PL                                        ______________________________________                                        `PS-776` 33       1499     20.4     0.20                                      `PS-118` 43       1351     21.7     0.12                                      `SELVA`  90       1414     22.8     0.20                                      ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                        Comparison of primary fruit characteristics of `PS-776`,                      `PS-118` and `Selva` from Salinas, California, July 27, 1995.*                CHARACTER   `PS-776`   `PS-118`   `SELVA`                                     ______________________________________                                        Munsell Color                                                                             7.5R 3/8 to                                                                              7.5R 3/10 to                                                                             7R 4/11**                                               7.5R 3/10  7.5R 2/8**                                             Fruit Length                                                                              3.5        3.8        4.4                                         mean (cm)                                                                     Fruit Width 3.3        4.0        4.2                                         mean (cm)***                                                                  Calyx Diameter                                                                            3.7        5.4        4.1                                         mean (cm)                                                                     Sepals/Berry                                                                              14.1       15.0       15.8                                        mean                                                                          ______________________________________                                         *`PS118` and `Selva` evaluated July 17, 1995.                                 **`PS118` and `Selva` fruit color according to Nelson et al, U.S. Plant       Pat. No. 8,205.                                                               ***Width is measured across the widest part of the berry, typically acros     the shoulders.                                                           

                  TABLE 3                                                         ______________________________________                                        Comparison of 1994 fruit quality characteristics of `PS-776`,                 `PS-118` and `Selva`, from Salinas, California.*                              CHARACTER    `PS-776`   `PS-118` `SELVA`                                      ______________________________________                                        Skin Firmness                                                                              8.0        8.3      7.6                                          Fruit Appearance                                                                           8.3        7.7      6.8                                          Fruit Gloss  8.0        8.2      6.6                                          ______________________________________                                         *Results are from replicated holding tests performed from April through       October 1994 in Salinas, California. Ratings are based on a scale from        1-10; the higher the rating, the stronger the skin and the more attractiv     and glossy the berry.                                                    

                  TABLE 4                                                         ______________________________________                                        Comparison of 1995 flavor test summary of `PS-776`, `PS-118`                  and `Selva`.*                                                                 CHARACTER    `PS-776`   `PS-118` `SELVA`                                      ______________________________________                                        Rating       2.6        3.5      2.4                                          ______________________________________                                         *Results are an average of 3-4 flavor tests from fruit harvested from         Salinas, California after being held for 2-3 days in cold storage. Rating     are based on scores of 1-5, 5 being the best.                            

The fruit of `PS-776` is medium-small in size and characteristicallyconic in shape. Primary berries are typically longer than wide withlongitudinal creases and irregular shapes occurring infrequently. Thesecondary and tertiary berries are also typically longer than wide andsymmetrically conic in shape. The fruit surface is medium to deep red incolor with a very light colored flesh to white at the core. Table 2summarizes fruit comparison characteristics.

The fruit surface is typically smooth with the seeds generally heldflush to the surface with some seeds protruding slightly from the fruitsurface. The seeds are yellow and only darken slightly with prolongedexposure to direct sunlight. The seeds are spaced evenly over thesurface of the berry with seedy tipped fruit rare except for earlyspring primary berries which may have seedy tips. The fruit becomes moreuniformly shaped producing seedy tips rarely during the summer and fallmonths. The skin of the fruit is considered firm, with good gloss andacceptable flavor. Tables 3 and 4 summarize fruit quality and flavorcharacteristics, respectively.

The calyx of the primary berry is relatively small in diameter with someoverlapping sepals. The calyx attaches slightly below the base of thefruit with necked fruit very uncommon. The sepals are elliptical toovate in shape with acute apexes and very few serrations. Fruit skin isconsidered very susceptible to cracking due to rain. Pollination may beaffected by rain resulting in seedy tipped fruit and small malformedberries.

PLANT CHARACTERISTICS

The plant of `PS-776` is medium in size with multiple crowns producingvery few runners when given the proper chilling levels prior to beingdug, and artificially, prior to being planted. Excessive chilling willresult in an over-vigorous plant with a reduction in total fruit yieldand increased runner production. Although the plant may become overvigorous if provided with excessive field chilling and/or artificialcold storage prior to being planted, it generally does not become toolarge unless chilling and/or storage levels greatly exceed acceptablelimits. The plants grow slowly during the winter and spring months afterplanting, but by early summer have reached good vigor. The foliage growsupright on relatively long thin petioles. The plant canopy remainsrelatively open if exposed to the proper chilling and cold storagelevels, but may become slightly more dense if over-chilled and/orover-stored. The plant canopy has a relatively medium-coloredappearance, yet may appear lighter than normal due to the greaterinflorescence exposure above the plant.

FOLIAGE CHARACTERISTICS

`PS-776` foliage characteristics are compared to those of `PS-118` and`Selva` in Table 5.

                  TABLE 5                                                         ______________________________________                                        Comparison of leaf characteristics of `PS-776`, `PS-118` and                  `Selva` from Salinas, California, May 19, 1995.                               CHARACTER   `PS-776`    `PS-118`  `SELVA`                                     ______________________________________                                        Munsell Leaf Color                                                                        7.5GY 3/4 to                                                                              7.5GY 3/4*                                                                              7.5GY 4/4*                                  (upper surface)                                                                           7.5GY 3/6                                                         Terminal Leaflet                                                                          7.7         8.4       9.8                                         length mean (cm)                                                              Terminal Leaflet                                                                          7.4         7.7       8.3                                         width mean (cm)                                                               Terminal Leaflet                                                                          1.04        1.09      1.19                                        ratio (L/W)                                                                   Petiole Length                                                                            19.9        20.1      19.8                                        mean (cm)                                                                     Petiole Width                                                                             4.4         4.7       5.2                                         mean (mm)                                                                     Petiolule Length                                                                          9.7         10.0      10.8                                        mean (mm)                                                                     Serrations/Leaf                                                                           25.7        20.7      24.9                                        Serration Depth                                                                           4.3         5.8       5.2                                         mean (mm)                                                                     ______________________________________                                         *`PS118` and `Selva` leaf color according to Nelson et al., U.S. Plant        Pat. No. 8,205.                                                          

The foliage of `PS-776` is relatively small in size, non-glossy, mediumin color and lightly rugose. The terminal leaflet is nearly as wide aslong as described by the length/width ratio. Table 5 summarizes foliagecomparison characteristics. Leaflets have many relatively small andshallow serrations at the margins with moderately acute apexes. Theseserrations typically occur singly with many leaves having small doubleserrations the point where the serrations join. Petioles are consideredlong and thin in diameter with bract leaflets commonly occuring singlyor in pairs. Petioles are medium in length. Pubescence on the petiolesgrows irregularly perpendicular to the petiole and irregularly parallelto the upper and lower leaf surface.

FLOWERS AND INFLORESCENCES

`PS-776` inflorescence characteristics are compared to those of `PS-118`and `Selva` in Table 6.

                  TABLE 6                                                         ______________________________________                                        Comparison of inflorescence characteristics of `PS-776`,                      `PS-118` and `Selva` from Salinas, California, July 27, 1995.*                CHARACTER       `PS-776` `PS-118`  `SELVA`                                    ______________________________________                                        Inflorescence Length                                                                          36.3     30.8      36.0                                       mean (cm)                                                                     Primary Peduncle                                                                              26.2     19.0      20.0                                       Length                                                                        mean (cm)                                                                     Primary Peduncle                                                                              3.4      4.2       4.2                                        Width                                                                         mean (mm)                                                                     Primary Pedicel 4.9      6.3       9.0                                        Length                                                                        mean (cm)                                                                     Primary Pedicel 1.8      2.3       2.5                                        Width                                                                         mean (mm)                                                                     ______________________________________                                         *`PS118` and `Selva` evaluated July 17, 1995.                            

The inflorescence of `PS-776` is long, extending the flowers and fruitbeyond the foliage during much of the season. The inflorescence remainsupright, visible above the plant canopy much of the year, until theweight of the ripening fruit causes then to fall to the sides of thebed. The primary peduncle is considered long and thin, especially at thetime of the evaluation. The pedicel holding the primary berry isconsidered short and thin and may originate singly from the apex of theprimary peduncle or from one of the secondary peduncles. Secondary andtertiary berries are borne on pedicels arising from secondary peduncleapexes. Anthocyanin coloration (color near 5R 4/8) is present on exposedsurfaces of primary pedicels and secondary and tertiary pedicels andpeduncles. Table 6 summarizes inflorescence comparison characteristics.

Flowers are medium in size and readily seen above the canopy of theplant during much of the season. Anthers produce ample pollen for goodpollination except during the early season and rainy periods when seedytipped fruit may occur. Flowers produce an average of 6 to 9 smallobovate shaped petals per flower. Typically a bract leaf is borne on ashort petiole which originates at the primary peduncle apex alongsidethe base of one of the secondary peduncles. Bract leaves may also occurat the apex of secondary peduncles. Pubescence occurs on all pedunclesand pedicels, growing irregularly perpendicular to both these surfaces.

ISOZYMES IN LEAF EXTRACT

`PS-776` isozyme banding characteristics are compared to those of`PS-118` and `Selva` in Table 7.

                  TABLE 7                                                         ______________________________________                                        `PS-776` Isozyme banding patters compared to `PS-118` and                     `Selva`.                                                                      CULTIVAR         PGI         PGM                                              ______________________________________                                        `PS-776`         A2          C4                                               `PS-118`         A7          C4                                               `Selva`          A2          C2                                               ______________________________________                                    

Studies of protein polymorphism in strawberry by the starch gelelectrophoresis method were conducted at Plant Sciences, Inc. tocharacterize this newly developed variety and distinguish it fromsimilar appearing varieties.

Isozymes were extracted from young leaves and characterized, usingstarch gel electrophoresis techniques. The following isozmes werecharacterized: phosphoglucoisomerase (PGI:EC 5.3.1.9) andphosphoglucomutase (PGM:EC 2.7.5.1).

The testing used both field and greenhouse grown plant material, allgrown in Watsonville, Calif. Newly mature leaves (0.5 g fresh weight)from the growingcrowns were used. Samples collected in the morning, heldat 4° C. and analyzed within six hours.

The tissue preparation, extraction and staining methods utilized are asreported in S. Arulsekar and D. E. Parfitt, "Isozyme Analysis Proceduresfor Stone Fruits, Almond, Grape, Walnut, Pistachio, and Fig",HortScience 21(4): 928-933.

Following electrophoresis, the gel was sliced and stained for eachenzyme system. Banding patterns were interpreted as they developed andgel slices were fixed in 50% glycerol.

The isozyme banding patterns of `PS-776`, compared to `Selva` and`PS-118`, are given in FIG. 5. The pattern and band densities aredistinctly different between `PS-776` (C4) and `Selva` (C2) for the PGMenzyme system. The pattern and band densities are distinctly differentbetween `PS-776` (A2) and `PS-118` (A7) for the PGI enzyme system. Thecombination of isozyme patterns shown, derived from the specifictechniques described, identify `PS-776` with certainty as a uniquestrawberry variety.

A series of molecular markers have been assigned to this new variety forunique identification.

PEST REACTIONS

The new variety may not be resistant to any of the known insects,diseases or viruses common in California. It is known to be susceptibleto the two-spotted spider mite, aphid and flower thrip. It is also knownto be susceptible to grey fruit mold, angular leafspot and powderymildew. The susceptibility of the new variety to any of the viruscomplexes of California has not been determined.

We claim:
 1. A new and distinct variety of strawberry plant designated`PS-776`, as herein described and illustrated.